gistfile1.txt

  private static void Day3P1P2()
        {
            
            var data = File.ReadAllLines("Day3.txt");
            var fabric = new Dictionary<(int,int), List<int>>();
            foreach (var line in data)
            {
                var numbers = line.Split(new[] {'#', '@', ',', ':', 'x', ' '}, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToList();
                var id = numbers[0];
                var left = numbers[1];
                var top = numbers[2];
                var width = numbers[3];
                var height = numbers[4];
                for (int x = left; x < left + width; x++)
                {
                    for (int y = top; y < top + height; y++)
                    {
                        if (!fabric.ContainsKey((x, y)))
                        {
                            fabric.Add((x,y), new List<int>());
                        }                        
                        fabric[(x,y)].Add(id);
                    }
                }
            }
            var n = fabric.Count(e => e.Value.Count > 1);
            Console.WriteLine(n);
            var overlapping = fabric.Where(e => e.Value.Count > 1).SelectMany(e => e.Value).Distinct().ToList();
            Console.WriteLine(Enumerable.Range(1,data.Length).FirstOrDefault(h => !overlapping.Contains(h)));
        }